BACTERIAL-VIRAL INTERACTIONS AND MINERAL PRECIPITATION

Interactions between bacteria and bacteriophages (viruses that infect prokaryotes; also known as phages) have been examined in a wide range of environments. While authigenic mineral precipitation is common in many aquatic environments, interactions between bacteriophages and their hosts under mineralizing conditions have not been examined. This is an intriguing biogeochemical relationship to investigate as (i) bacteriophage attach to the same components in bacterial cell walls that attract dissolved mineral-forming elements, in the surrounding environment, (ii) long term viral infection of a bacterial cell (i.e., lysogeny) causes structural and compositional changes to the cell surface where phages and dissolved ions bind, possibly altering the reactivity of the attachment-sorption site, and (iii) the cell may become stressed during surface associated mineral formation possibly causing the induction of a lysogenic cell. Bacterial-phage interactions were examined under mineralizing conditions where mineral precipitation was actively occurring. Experiments were conducted using Bacillus subtilis and a temperate phage, SPbc2 under iron saturated conditions (0.1 mM ferric iron, near neutral pH) to induce bacterial mineralization. Bacillus subtilis mineralization resulted in a substantial decrease in phage replication (~ 98%). In addition, iron addition to lysogenic cultures did not induced viral lysis despite iron precipitation at cell surfaces. If the B. subtilis-SPbc2 results were applied to natural environments were bacterial mineralization takes place (i.e. acid mine drainage), bacterial mineralization would be advantageous to bacterial hosts as it protects the host against phage attachment and subsequent viral lysis. Moreover, lysogeny would be advantageous to phages as host mineralization drastically hinders phage replications.